


Up in Flames?

by Deku_Lily



Category: Undertale (Video Game)
Genre: Bad Puns, Birthday Party, M/M, Undertale Monsters on the Surface, annoying dog antics, birthday prompt, i think that's all i need, let me know if I need more tags, sfw
Language: English
Status: Completed
Published: 2018-10-20
Updated: 2018-10-20
Packaged: 2019-08-04 17:21:46
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,540
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16350917
Author URL: https://archiveofourown.org/users/Deku_Lily/pseuds/Deku_Lily
Summary: Grillby learns his boyfriend hasn't celebrated his birthday in some time. He wants to fix that, but sometimes the best-laid plans can go awry. But only a little, if you keep a cool head.





	Up in Flames?

**Author's Note:**

  * For [skerb](https://archiveofourown.org/users/skerb/gifts).
  * Inspired by [Postcards From Waterfall](https://archiveofourown.org/works/12509220) by [skerb](https://archiveofourown.org/users/skerb/pseuds/skerb). 



> This is a gift for the wonderful skerb who, without their fanfic, wouldn't have lit the fire in my belly to write anything Sansby. Go check out their fic! (99% SFW but still rated E for Explicit, plz mind the tags.)

* * *

 

Sans didn’t celebrate his birthday.

 

It was a revelation Grillby had after dating the skeleton for a while. But whenever the elemental asked Sans why he didn’t celebrate it he’d be brushed off, whether by deflection through humor or the subject being changed. He could tell Sans was hiding his discomfort by smiling. The one time Grillby got an honest answer out of him it’d almost broken his heart.

 

“ it’s not worth the trouble, ” was what Sans said. It was almost like he thought he wasn’t worth the “trouble.” Grillby wanted him to elaborate… but he could tell Sans wasn’t going to, no matter how gently he asked. So he dropped the subject, for a time, hoping patience would eventually reward him.

 

Over the following months they celebrated Papyrus’ birthday and Gyftmas together. Sans figured out when Grillby’s own birthday was and gave him a gift just before he left to celebrate with family. They started living together, for star’s sake! And yet, despite it all, the day of Sans’ birth  _ still _ went uncelebrated! 

 

Grillby decided he had enough. Although it felt like going behind Sans’ back he resorted to asking Papyrus about it. The tall skeleton surprised him, because he knew exactly why Sans no longer celebrated his birthday.

 

He laid all the blame at the paws of a little white dog that had plagued their lives since they moved to Snowdin. More Papyrus’ life than Sans’, but it seemed like the “infernal creature” always knew when Sans’ birthday rolled around. It would make itself into an even bigger nuisance than usual, foiling all attempts to plan a celebration. Papyrus couldn’t even hide a gift in his closet, because it would be chewed up like his special attack! 

 

Sans, ever the lazy one, decided it would be easier to forgo all future birthdays. He said he was more than happy with just a hug from his brother on the not-so-big day, and maybe a little less henpecking about his laziness and ketchup-drinking. Papyrus begrudgingly agreed to it all, but only because the annoying dog couldn’t spoil them! 

 

The information surprised Grillby. He didn’t see such a dog during any other celebration he’d been a part of. Papyrus could only shrug, saying the thing was remarkably selective in its methods of annoyance. It was like it took the time to calculate the best way to vex them, giving them a grace period before confounding them once more. 

 

When asked why the dog didn’t go out of its way to ruin Papyrus’ last birthday he said he had no clue, and confessed that the dog had never ruined his birthday. He speculated that he was left alone on that one day out of gratitude for all the bones he let the dog pilfer from him the rest of the year. It was the only explanation that made sense. 

 

It was proof the dastardly canine did everything on-purpose!

 

Setting Papyrus’ paranoia aside, Grillby decided he wanted to plan a party for Sans, anyway. Papyrus rolled his eye sockets at him but provided the date. It turned out he only had two weeks to work with so he got straight to it. He ignored Papyrus as he said, “ DON’T SAY I DIDN’T WARN YOU! ” 

 

The first thing he did was to print a flyer to hand out in the restaurant, inviting the old regulars from Snowdin to the celebration he hoped to throw in his restaurant. But before he could take them into work they were mysteriously demolished, their remains littering the floor of his home office. A second attempt to print more ended the same way. After a moment of thought he figured a smaller, more intimate celebration was in order. He enlisted Papyrus’ help to invite Sans’ closest friends to celebrate in their home, which seemed to appease the mysterious paper-shredding force (which may or may not have been Papyrus’ annoying dog.) He continued planning in peace, until his next hurdle.

 

He heard about a cake made with ketchup and found a recipe online. He printed it out… but before he could bake one up as a test the recipe went missing. He looked high and low before finding it torn to shreds on his back porch. He didn’t bother reprinting, figuring he could just read the recipe off his phone. Before he did so, he was struck by the thought of whether or not the paper-shredding force would give the same treatment to the rather important device. Not wanting to take that chance, he decided to try making individually-sized chocolate lava cakes, drizzled with chocolate ganache. This, too, seemed to appease the paper-shredder. 

 

Grillby was stumped as he tried to think of an appropriate present. What did one get for an intelligent, funny skeleton monster that asked for nothing? He went online and almost bought an expensive new telescope for his star-gazing lover… but had second thoughts and decided to give himself more time to mull it over. He did so as he walked down the street one day, passing by a human trying to walk an entire pack of dogs as they went absolutely bonkers over something. While the dozen or so dogs of various sizes were quite a spectacle, barking up a tree at nothing, it was the t-shirt the human wore that’d caught his eye. 

 

It was a black shirt with a picture of a bone printed on it, along with the caption of “I found this humerus.” The human was kind enough to tell him the name of the website they got it from, though they had to shout to be heard over the barking. It turned out there was a sale, so Grillby was able to get another shirt at a discount (the second one saying, “A good pun is its own reword.”) 

 

Upon reflection, ordering a nice telescope  _ and _ having something that big shipped to his home in time for the party might’ve stretched Grillby’s budget by too much. At least the express shipping for the shirts was reasonably priced. He thanked his good fortune at having crossed paths with that human, and wished the poor soul better luck the next time they walked that many dogs. When the gifts arrived he wrapped them and hid them on the shelf in his closet, confident Sans wouldn’t bother to look for them that high up. Unlike Papyrus’ past gifts his were left in one piece, giving Grillby the feeling that he’d made the right choice. 

 

The big day finally arrived. It was fortunate that it fell on the same day as a human “federal holiday,” on which he’d already planned to close the restaurant for the day. That gave him plenty of time to decorate after Papyrus got Sans out of the house, but before the guests arrived. It’d been difficult to find a way to balance something his low-key boyfriend might like and actually making it clear a celebration was taking place, but Grillby was satisfied with the result. 

 

Despite the hiccups in the previous days, things seemed as though they’d go well. 

 

The guest list was rather short and consisted of Frisk, Toriel, Dr. Alphys and her plus-one Undyne and, naturally, Papyrus. Asgore had declined his invitation with regret, citing unavoidable appointments he’d already made. However, he  _ did _ send a gift along via Frisk, which was nice of him. Then again he’d always been that way, so it wasn’t really a surprise. 

 

The gifts were all piled onto the coffee table in the living room. Dinner would be something everyone could enjoy (including health-conscious Papyrus.) Toriel had been kind enough to contribute a snail pie to the dinner, a dish Grillby had never heard of, which was bound to be a novel experience. The cakes were baking and would be cool enough for those not made of fire to enjoy by dessert time. Grillby felt better and better about everything as the clock ticked down.

 

Papyrus had taken it upon himself to keep Sans from taking a shortcut home before everything was ready. He’d done so by dragging his brother to an automotive store to “help” him pick out new accessories for his car. Which meant Sans was there to hold the chosen seat covers and cleaning/waxing products, making car-related puns while he did (which he shared via texts with Grillby and, judging from her snickering, Toriel.) The supposed point of the outing was so they could “hang out in a brotherly fashion,” as Papyrus had said. It was probably the only reason Sans went along with the idea.

 

Despite all the jokes he made at his brother’s expense he really did care for Papyrus, no matter how hard he tried to hide it. It was one of his most endearing qualities.

 

At one point Grillby received a short video from Sans. The skeleton had neon pink, over-sized, fuzzy-looking dice jammed into his eye sockets. The way his grin was wider than normal made Grillby smile, too. Sans could barely restrain his chuckles as he said, “ guess my luck ran out. i just rolled snake eyes. ” The video ended not long afterward, but Grillby could hear the beginning of Papyrus’ groan of fraternal annoyance and embarrassment. Fortunately, instead of ditching Sans, he stayed strong and managed to endure until it was time to come home for the “completely ordinary late lunch.” 

 

Grillby and the others hid when they heard Papyrus pull into the driveway, the elemental crouching to the floor behind the couch. The sound of Sans’ key sliding into the locks made his soul flutter. He hoped Sans liked everything. He hoped this would be an actual surprise and that he hadn’t found everything out already. He hoped he wouldn’t be angry with him for making a fuss. He just wanted Sans to be  _ happy _ . He began to tremble with a combination of anticipation and trepidation as the door opened.

 

“ we’re home! ” The door was shut and locked. Sans’ shuffling footsteps and Papyrus’ livelier pace got louder as they approached the living room. “ grillbz? you here, babe? ”

 

“ IT WOULD SEEM THAT GRILLBY HAS STEPPED OUT, FOR A MOMENT! ” said Papyrus. “ PERHAPS HE IS -AHEM- WATERING THE PLANTS? ” The wink he gave Sans was audible, and Grillby shook his head at the agreed-upon “wait for it” signal. He could just imagine the look of confusion on Sans’ face…

 

“ huh? what’re you- hey! ” The question was cut off as Papyrus pushed Sans into the living room. That was everyone’s cue to jump out of their hiding places. 

 

The guests pulled party poppers as they and Grillby shouted, “SURPRISE! Happy birthday, Sans!” 

 

Sans’ dumbfounded face made Grillby chuckle as he took everything in. He finally focused on Grillby, his eyes still disbelieving as he said, “ babe? is this what i think it is? ”

 

Stepping closer, Grillby nodded.  _ “If you think it’s a birthday party, it is,” _ he said. Leaning closer, he asked in a low voice,  _ “What do you think?” _

 

Sans’s orbits widened, somehow picking up on Grillby’s anxiety despite how he tried to keep it under wraps. He took a warm hand into his phalanges as he said, “ it’s great! it’s great, babe. totally. it’s just… ” Sans’ grin came back and he started laughing, taking another look around the room. “ heheh heh! oh, man, you really pulled it off, didn’t ya? i’m impressed. there, uh, weren’t any  _ difficulties _ , were there? ” He raised a brow ridge at Grillby, who shook his head.

 

_ “No more than in any other event I’ve ever planned,”  _ he said. He gave his love a peck on the forehead, smiling as he silently pulled Sans toward the dining room. 

 

The bright smile Sans gave him in return could have put the sun to shame.

 

~~~~~***~~~~~***~~~~~***~~~~~

 

Sans crept through the house quietly, taking care to avoid the squeaky floorboards as he descended to the ground floor. He already missed the warmth of his lover’s arms… but his new “humerus” t-shirt was helping to keep some residual heat close to his bones. It would have to do, for the moment. There was something he had to do before he could go back to bed. 

 

He stepped out onto the back porch and whistled softly through his teeth. He only had to wait a moment before his little buddy appeared as though from nowhere, yipping happily. Little paws were placed on his ribs as the dog tried to lick his face. It couldn’t quite reach him, but it stopped trying as Sans used both hands to scratch it behind the ears.

 

“ thanks, buddy, ” he said. “ when i asked ya all those years ago to keep my birthday from being a bummer, i didn’t think you’d pull off something like this! ”

 

He loved Papyrus, he really did, but his brother’s idea of a “great” birthday was  _ exhausting! _ And his taste in presents was… unique. So, when a certain little dog started crashing their parties, anyway, Sans knew he’d found a way out of the things that (hopefully) wouldn’t hurt Papyrus’ feelings. 

 

The arrangement had worked for  _ years _ , although Papyrus’ mounting frustration had been a bit hard to handle, after a time. Which was why he convinced his little buddy to leave his brother alone on certain days. He paid for it with bones, but it was worth it just to give Papyrus one less thing to worry about for a day. Eventually he offered to stop having a birthday altogether, to save his brother (and himself) a little more stress. That stress was part of why he’d been so reluctant to tell Grillby about his birthday. For all the good it did. Not that he was complaining!

 

This year’s party had been great. Great food (despite the way Toriel’s pie “mysteriously” disappeared), great friends, and fun gifts. Even Papyrus’ gift had survived this year! But the gifts that really warmed the cockles of his soul were the shirts from Grillby. He really was a lucky guy to land a hot boyfriend that knew him so well.

 

He’d learned all about Grillby’s “mysterious paper shredder.” That he was so quick to consider alternatives whenever his original plan went to hell was a testament to his mental flexibility. Sans wondered if it came with running a business for so long. It was just another checkmark in the “why Grillby is the best boyfriend” column. (The titles of “the coolest/greatest/best brother” would always belong to Papyrus.)

 

Sans shook himself out of his thoughts and gave the little white dog its usual payment of bone constructs. The little guy had earned them. But as great as the party today had been, Sans knew any birthday Grillby planned was going to have tough competition in Sans’ soul as “the best one ever.” That was because one year ago, on this very day, he’d confessed his feelings to Grillby, only to get the best birthday gift he’d ever received in his life…

 

He learned the elemental felt the same way. That was always going to be a tough act to follow, but he looked forward to watching Grillby try and do just that. 

 

Sans’ usual grin warmed as he went back inside. If he had his way, he and Grillby would have a LOT of birthdays to celebrate together.

* * *

 


End file.
